Michigan Rep. Fred Upton announced Friday he will run for re-election instead of trying to challenge Democratic Sen. Debbie Stabenow in 2018.

“I will not be a candidate for the U.S. Senate. There was a path, but today we are choosing not to follow it,” the Republican lawmaker said in a statement. The former chairman of the Energy and Commerce Committee had been publicly weighing a Senate bid for much of this year.

Indiana Rep. Luke Messer is expected to run for Senate but has yet to make an official announcement. (Tom Williams/CQ Roll Call File Photo)

It’s no secret that a handful of House members are mulling bids for the Senate next year, with several of them all but running their 2018 races already.

Most are in no rush to officially announce their Senate campaigns. Sixteen months is a long time to face the barrage of attacks that comes with running statewide. And in an uncertain political environment, candidates may be taking longer to test the waters.